Automobiles and other vehicles provide a significant portion of transportation for commercial, government, and private entities. In some situations, a vehicle (such as an autonomous vehicle) transports passengers from a pick-up location to a destination location. For example, an autonomous vehicle may receive a transport request from a particular user. When fulfilling the transport request, the autonomous vehicle needs to identify the correct passenger at the pick-up location and transport that passenger to the desired destination location. Additionally, the passenger making the transport request needs to identify the correct autonomous vehicle that is fulfilling the transport request. Autonomous vehicles that do not have a human operator need to provide systems to automatically identify passengers and monitor passenger activity.